Electrical lubrication of detergent shaping devices



May 29, 1956 R. c. HEAD ELECTRICAL LUBRICATION OF DETERGENT SHAPING DEVICES Filed Feb. 26, 1955 y WM M 4 5 ywv y d wax, C013 swa wail United States Fatem G ELECTRICAL LUBRICAT ION OF DETERGENT SHAPING DEVICES Robert C. Head, Glendale, Ohio, assignor to The Procter arfld lGamble Company, Ivorydale, Ohio, a corporation 0 io Application February 26, 1953, Serial No. 338,947

3 Claims. (Cl. 204-180) The present invention relates to means and methods for lubricating the interface between plastic detergent compositions and other materials, and particularly for the improvement of the surface of plastic detergent compositions and other benefits by the passage of an electric current across the interface between the plastic detergents and other materials in contact therewith.

The shaping of plastic detergent compositions, for instance in the formation of bars of soap or other detergents, by methods such as cutting with wires or knives, extruding through orifices, molding, and stamping, is beset With the difliculty that the friction and/ or adherence of the detergent composition to the shaping device over which it passes is at times so great that the surface of the detergent composition tears, leaving a rough surface except when very narrow limits of composition and operating conditions are used. Without the benefits of the present invention it is thus often necessary to choose formulas which will insure the production of smooth surfaced products but which are not otherwise ideal, thus frequently producing finished bars that are soft, mar readily, or absorb water too readily. In general, such factors as electrolyte and moisture contents, and temperature which normally will be employed will vary considerably, depending upon what polymorphic phaseof the detergent is desired, and whether a framed, milled or other extruded product is being made. Typical variations in polymorphic phases encountered in the production of plastic detergents are described by Ferguson, Rosevear and Stillman in Solid Soap Phases, J. I. E. C. 35, 1005-1012 (1943); by Ferguson in The Four Known Crystalline Forms of Soap, Oil &.'Soap, pp. 6-9, January 1944; by Wood in U.'S. P. 2,580,713 entitled, Plastic Detergents and Methods For Making Same; and by Broome, Hoerr and Harwood in an article entitled The Binary Systems of Water 'With Dodecylammonium Chloride and its-N-Methyl Derivatives,J. A. C. S. 73, 3351 (1951).

This invention has for its objects improvements of physical properties of detergent bars and improvements in methods for shaping them.

It is an object to broaden the range of operating conditions and formula compositions wherein a bar with a smooth surface can be shaped.

Bar detergent products high in beta phase content may be made by agitating a partially solidified mass of the detergent within a critical temperature range, and extruding the partially solidified mass as described in Mills Patent 2,295,594 with reference to soap. The critical temperature below which beta soap may be formed by mechanical agitation is in all cases low enough to permit extruding the soap in a form-retaining condition. The temperature of the soap as extruded in the Mills process is kept above a lower limit at which the mass substantially loses its pasty cohesiveness. A product is formed which is softer and less tough and translucent than milled soap of like formula. I use the term pasty cohesiveness to describe that property of soap, at the point of extrusion within said operating range, which enables freshly sep 2,748,070 Patented May 29, 1956 arated masses of said soap to become reunited when brought together without requiring the application of high pressures such as are employed in plodding milled soap. The extruding soap mass, in the state of pasty cohesiveness, may be considered as a thick pasty magma consisting of a mixture of solid soap crystals in a viscous matrix of unsolidified soap. This state of pasty cohesiveness is not limited to soaps but is also obtained with synthetic detergents and their mixtures with soaps. The unsolidified portion of soap in this state is usually primarily in the neat phase when the inorganic salt content is low, however in compositions of higher inorganic salt content such as are frequently experienced with the anionic synthetic detergents the neat or anisotropic phase may frequently be in part or entirely replaced by an isotropic phase, for example the nigre phase. Such isotropic phases may vary considerably in composition, as for example, from the so calledthick nigres of high detergent content to others of such low detergent content that they are often classified as nigre lyes or lyes.

With many detergent formulas a smooth surface on the extruded detergent bar is obtainable only within narrow temperature ranges, and if one wishes to operate outside these ranges it becomes necessary to shave off the rough surface of the extruded bar in order to obtain a presentable product.

One of the principal objects of this invention is to enable one to produce smooth surfaced extruded detergent products, high in beta content, by the aforesaid Mills process over a wider range of extrusion temperatures than is otherwise possible.

Another object is to facilitate the complete removal of solidified or partially solidified detergent compositions from molds through the electrical lubrication of the interface between the molds and said detergent composition.

I have discovered that the passage of a direct electric current through a detergent composition lubricates the interface between the detergent and at least one of the electrodes. I have further discovered that this phenomena can be utilized to advantage in shaping of detergent compositions. Thus if a direct electric current is caused to flow across the interface between a plastic soap composition and the device used for shaping it, such as--e. g. molding, cutting, stamping or extruding devices, with theshaping device serving as a lubricated electrode, I have found that the detergent composition moves across said electrode much more smoothly and readily than if the electric current were not flowing.

I have further discovered that a smooth surface is produced by the above procedure in a much wider range of temperature and furthermore a smoother surface is obtained than without the aid of the present invention.

In the accompanying drawings:

Figure 1 illustrates a preferred form of orifice for use in the application of this invention to the extrusion of detergents;

Figure 2 is a cross-sectional view on the line Z-2 of H Figure 1;

v and molds for large bars or blocks of detergents, commonly referred to as frames. Also included are continuous molding devices wherein the molds may comprise endless belts or a plurality of interlocking segments.

In'the development of this invention I have discovered that when a direct electric current is passed through a plastic detergent composition there apparently is a gradual migration of the liquid dispersing medium to one electrode, which phenomena 1 shall refer to as electroendosmo'sis. in general, particularly if the dispersing medium is water or a water rich phase the migration of the water therein will be toward the negative electrode, commonly called the cathode. In this case the solid material has assumed a negative charge when dispersed in the water which causes the solid matter to be attracted to the positive pole, called the anode. At times, however, materials are encountered that assume a positive charge in water and in these instances the water will migrate to the anode. If now the water is replaced by an organic liquid the charge assumed by the dispersed solid will occasionally be reversed and likewise the migration of the materials involved will be reversed. Ordinary soap, for example, assumes a negative charge when dispersed in water. Here then the water migrates to the cathode.

I have also discovered that with those detergents which contain electrolytes the electric current also produces electrolysis. Thus, for example, with ordinary soaps made from the sodium salts of higher fatty acids, there is evidence that metallic sodium is deposited at the O cathode. Of course, as soon as it contacts the water, which also has migrated to the cathode, it reacts to form sodium hydroxide, which may be detected by acid-base indicators such as phenolphthalein. In the practice of the invention with ordinary soaps the cathode is generally the preferred electrode at which to obtain the desired electrical lubrication. However, electrical lubrication may also be obtained at the anode, possibly due to the deposition of fatty matter at the anode interface but more probably due to the greater amount of heat developed as a result of the greater electrical resistance of the soap layer at the anode interface caused by migration of water away from this electrode. It is obvious that as one changes from anionic to cationic detergents and also includes organic dispersing mediums, such as oleaginous superfatting agents, each specific combination of materials will call for an appropriate choice of polarity of electrodes.

in the practice of this invention I contemplate its use in the manufacture of framed, extruded and molded plastic water soluble anionic organic detergents consisting essentially of ordinary water soluble soaps (e. ,g. the alkali metal salts of higher fatty acids) and/or water soluble anionic synthetic detergents, particularly those synthetic detergents that are sulfate or sulfonate tives 'of organic compounds that contain in their molecular structure an alkyl group containing from 8 to 18 carbon atoms, e. g. the alkyl 'sulfa-tesand sulfonates, alityl aryl sulfonates, fatty glyceryl sulfates and sulfonates, alkyl sulfoacetates, sulfoacetic i'mido alkyl esters of fatty acids, etc.

The terms consisting essentially of as used in the following claims is intended to exclude the presence of other materials in such amount as to interfere substantially with the properties or characteristics of the compositions essential to the operation of the process described, but to permit the presence of other materials in such amounts as not substantially to affect said properties and characteristics adversely.

Numerous organic and inorganic building and improving agents may be incorporated with the anionic organic detergents, typical examples of such agents being the chlorides and carbonates of sodium and potassium, the sulfates of sodium, potassium and magnesium, calcium sequestering phosphates, alkylol mono and di amides, non-ionic detergents, fatty acid monoand diglycerides, etc. This invention is particularly applicable to soap processes such as are set forth in the Mills Patent'No. 2,295,594 wherein the soap at the time of extrusion contains some neat soap but also contains crystals of beta phase soap produced by the combined effects of mechanical action and temperature and is still in a condition of pasty cohesiveness as will be noted.

In order to facilitate an understanding of the invention, a preferred form of apparatus for one application of this invention is illustrated in the drawings. it will be understood that no limitation of the scope of the invention is thereby intended, the practice of the invention with other forms of apparatus capable of accomplishing the desired purpose being contemplated.

Figures 1 and 2 show an orifice suitable for use with electrical lubrication. The rectangular cutting edge ll which defines the opening is of metal and is clamped in position between abutting plates 12 and 13 of insulating material, for instance a resin plastic, the insulating plates being fastened together with bolts 14. The rectangular metallic orifice 11 which serves as an electrode, the electrical connection lug 1'5 and interconnecting sidearm 16 may be fabricated from the same piece of metal. A bolt 17 is provided for connecting the lug 15 to an electric conduit '18 supplying direct current as illustrated in Figure 3 where the orifice assembly, shown in Figures l and 2, is clamped in the nose of an apparatus used for agitating and extruding detergent compositions, said apparatus being typical of the device shown in Figure '2 of Mills Patent 2,295,594. in the present illustration the body of the apparatus serves as the other electrode, the electrical conduit 19 being fastened to the body 2i) by means of a bolt 21.

A further application of equipment suitable for use in my invention is in the stamping of plastic detergent compositions wherein the metal dies used for impressing a design on the opposite faces of a detergent bar are charged with one electrical polarity (for exa.mplecathodic) and the walls of the die box are constructed of an electrically insulating material except for a metal band which contacts the bar around its periphery and serves as an electrode of opposite polarity (anodic), but which does not make direct contact with the cathodic dies on either side, as the bar is being stamped.

My invention is also applicable to such processes, among others, as cutting of soap bars by means of Wires as set forth in the Burt Patent 2,359,403, and extrusion of soap bars and cutting of same by means of wires as set forth in the Walter Patent 2,385,322, the Hunten Patent 1,903,920 and the Loveland Patent l,4l6,483. when the moisture content of the soap is normally no lower than about 14 percent, and normally no higher than about 40 percent; however, in the case of the anionic synthetic detergents and mixture thereof with soap these values may drop considerably lower. Bar soaps formed by chilling neat soap particularly in the absence of agitation (as in the third and fourth of these patents) as a rule contain spontaneously formed solid soap of omega phase, and frequently at least some spontaneously formed solid soap of beta phase. These may, as a rule, be cut and/or .formed into shape while only partially solidified, i. e. while still partially in the liquid neat soap phase. Bar soaps produced with or without agitation during the chilling operation may contain one or more of three crystalline soap phases, namely, beta, omega and delta. My process may advantageously be used in the preparation of. detergent bars comprising any of these solid phases.

Example I.-In a typical practice of the process de scribed in Mills Patent 2,295,594, a detergent composition was used, for the manufacture of an extruded floating bar soap, comprised of a mixture of alkali metal salts (wherein sodium and potassium werensed in a molal ratio of 4:1) of higher fatty acids derived from a mixture of 30 parts by weight of coconut "oil and '70 parts of taliow. This soap contained 18.2% water and about 0.55% of inorganic 'salts consisting mainly of chloride, sulfate, hydrox'ide rand carbonates of sodium. An extrusion orifice of "the'typ'e'illustrated h'ere'in'in Figures 1 and 2 was used. It produced an extruded soap bar of approximately 2.7

sq. in. cross section. Without the benefits of the present invention, it was necessary to extrude this particular soap within a half degree (plus or minus) of 155.8 F. in order to obtain a bar which was both form-retaining and had a smooth surface which did not require subsequent trimming. (I will call the temperature at which a soap is in this condition the normal extrusion temperature.) Below this range the soap was undesirably soft and insufiiciently form-retaining for easy handling, and above this range the soap had such a lack of surface cohesiveness in relation to its surface stickiness that the extruded bar sur face tore badly as it passed through the orifice, producing a very rough product. However, with the passage of a direct electric current of 3.9 amperes across the interface at which the orifice contacted the soap during the extrusion, using a potential of 212 volts (this involves an obvious hazard that must be guarded against as pointed out hereinafter) with the orifice serving as the cathode, and the body of the extrusion unit (e. g. element 19, Figure 3) serving as the anode (the shortest path of the electricity through the soap between the two electrodes being 2% inches) it was possible through the resulting electrical lubrication, to broaden and raise the range of soap extrusion temperatures in which a smooth surface could be obtained to a span of 157.3 to 160 F. The smoothest surface was obtained at 157 .8 F., and this surface was much smoother than that obtained without electrical lubrication in the normal extrusion temperature range of l55.8- 0.5 F. The bar also became much firmer and more resistant to marring than the smooth surfaced bars made without electrical lubrication. The degree of increase in firmness resulting from electrical lubrication was determined by a standardized test wherein gradually increasing pressure was applied to each bar until it was ruptured. The pressure reading obtained at the moment of rupture of the bar made with the benefit of electrical lubrication was 80 as compared to the much lower value of 67 obtained without electrical lubrication, indicating a 19% increase in firmness.

Firrnness tests made on bars from which the outside surface had been shaved off to various depths showed that there is a similar increase in firmness throughout the bar; however, there is also a marked skin effect or toughening of the bar surface. If an electrically lubricated bar of Example I and an otherwise identically prepared but not electrically lubricated bar be stroked gently with the fingers across their freshly extruded and quite warm surfaces, the surface of the bar that was not electrically lubricated abrades badly whereas the electrically lubricated surface is depressed by the same amount of pressure but does not abrade. It is of interest to note that this increased skin toughness of the surface of bars extruded through an electrically lubricated orifice is transient, and disappears in a few days, but persists long enough to be of great value during the cooling, stamping and packing operations.

The remarkable smoothing effect on the bar surface of electrical lubrication can probably be best illustrated by comparing the electrically lubricated bar made at 157.8 F. with the bar made at the same temperature but with out the benefit of electrical lubrication. The latter bar was exceedingly rough with ragged torn edes having rents about every half inch that measured about 7 inch in depth. The electrically lubricated bar, on the other hand, had a dense smooth surface, examination of which revealed that part of the smoothness could be attributed to the absence of part of the numerous microscopic air pockets that normally appear on the surface of a floating bar soap which has not been produced with the benefits of electrical lubrication.

I have found that heat is developed at both electrodes as the electric current passes through the soap. In the foregoing example, for instance, the temperature of the orifice itself rose to 196 F. In the process of extruding the soap, with the orifice serving as the cathode as in Example I, I have found that the temperature of the orifice should ordinarily not exceed 220 F., or approximately the boiling point of the soap. Note that this is not the temperature of the extruded bar soap but the temperature of the orifice and perhaps a skin deep surface layer on the extruded bar. When this orifice temperature exceeds 220 F., the bar surface frequently discolors and develops welts and blisters, possibly due to sudden evaporation of water at the bar surface caused by the superheating effect of the excessively hot orifice. However, I find that there are some exceptions such as the following case:

Example Il.-Herein a soap was used comprised of the sodium salts of higher fatty acids derived from a mixture of 20 parts by weight of coconut oil and parts of tallow. This soap contained 20.2% by weight of water and about .50% of inorganic salts consisting mainly of chloride, sulfate, hydroxide and carbonates of sodium. Without the benefit of electrical lubrication this soap ex truded with a smooth surface within a range of only three degrees, namely 156 /2 :1 /2 F. However, very smooth electrically lubricated bars were produced throughout temperatures ranging from 153.3 to 160 F. Operating conditions are shown for three such electrically lubri- In the case of batch A an exceedingly high orifice temperature (390 F.) was obtained. The extruded bar surface did not blister or discolor in this case, perhaps because of the large increase in conductivity exhibited by the soap as the extrusion temperature is dropped from 159.5 to 153.3 F., there being almost twice the current flow in A as compared with B, at approximately the same voltage. It is my belief that this brought suificient water to the surface to prevent blistering and discoloration.

It is possible to produce a smooth surfaced electrically lubricated bar at 6 to 8 F. above the normal extrusion temperature, however, the surfaces of these bars are very brittle and may often develop surface cracks when stamped. The large amount of current may also frequently overheat and discolor the bar. In general a temperature range of 3 to 4 F. above the normal extrusion temperature is optimal for best results in both the extrusion and stamping operations.

Despite the fact that there is some heat added to the soap through electrical lubrication, the extrusion of the soap at about 3 to 4 F. above the normal extrusion temperature effects an overall reduction in the heat that must be removed in the process of cooling and converting a molten soap to a plastic soap high in beta phase. This permits a decrease in the amount of refrigeration needed, and thereby reduces the cost of the chilling operation.

When practicing the invention in the extrusion of high beta content soap of between 16% and 22% water content, using an orifice having a periphery of about 8 inches, electrically lubricated orifice surface areas in contact with the soap of between 0.1 to 7 square inches, and bar extrusion rates of about 0.9 to 2 linear feet per second good electrical lubrication results have been obtained with a current flow in the neighborhood of .5 to 6 amperes, using electrical potentials in the range of about to 320 volts, and the use of current flows even above and below this preferred range is contemplated. In the above work the minimum distance between electrodes has been about one inch. It has been found that by reducing this interelectrode distance; the electric potential used may be angers dropped well below the above 90 volt value and the use of potentials below 40 volts is contemplated.

Generally I have found that 3 to 5 coulombs of elec trical energy per square foot of extruded bar surface give excellent results. However, very good lubrication has been obtained at values lower than 0.7 coulomb/sq. ft. and also at about 7 coulombs/sq. ft. I have not found it necessary to exceed 10 coulombs/sq. ft. or drop below 0.1 coulomb/ sq. ft. in any case thus far. lt'appears that the effectiveness of the lubrication obtained per unit of electrical energy will be determined to a'large extent by the distribution of the energy, for example the division of power used for (1) electrolytic and electro-endosmotic eifects and (2 overcoming the electrical resistance at the orificedetergent interface. Thus in cases where the area of the orifice-detergent interface is decreased there is frequently a marked increase in the energy expended in overcoming tie interfacial electrical resistance, which also may vary greatly with the moisture and electrolyte content, and temperature of the detergent and, particularly with the current density used at the interface. Although I have preferred to use current densities at the orificedetergent interface of from 0.5 to 5.0 amperes per square inch, I have also obtained good electrical lubrication using values ranging from below .2 ampere per square inch to much higher current densities of about 2 amperes per square inch. (Only the electrically conducting portion of the orifice at the orifice-detergent interface, e. g. the surface between the cutting edges 11 and the insulated edge 22 of the metal orifice in Figures 1 and 2, is used in calculating the interfacial current densities.) I have not found it necessary to exceed 25 amperes per square inch nor to exceed a potential of 400 volts but contemplate the use of current densities and potentials both above and below these values with similar variations in the total electrical energy used per unit of extruded soap area.

Extruded bars such as those described above are cut into approximately uniform lengths, cooled, and again may be cut into shorter segments before stamping. It is found, as illustrated in Example III, that with the aid of electrical lubrication the cutting devices produce a smoother surface in severing the freshly extruded bars.

Example IH.The soap used in this example was like that used in Example I. With the extruded soap bar at a temperature of 158 F, segments were cut from the bar simultaneously with three wires which served respectively as (1) anode, (2) cathode and (Illa-control through which no current was passed. Using a potential of 9.0 volts across the anode and cathode, which were 1%" apart,

that caused a current of 0.3 ampere per lineal inch of cathode to flow through the soap, and with the cutting wires moving through the soap at a rate of aboutfi inches per second, cut surfaces were produced by the anode and cathode thatwcre both smoother than the surface produced by the nonelectrically-lubricated wire; the surface produced at the anode being somewhat smoother than that produced at the cathode.

The method employed for cutting extruded detergent bars .to uniform lengths or trimming bars to uniform and/or smooth shapes may vary greatly. Thus in some instances the multiple wire method used above may be employed wherein adjacent wires in the bar cutter are of opposite polarity. In other instances it may be desirable to apply :the same polarity to .all of the electrically lubricated shaping devices and apply .theopposite polarity to the supporting devices which may be electrically .conducting table tops or conveying belts.

The next example illustrates an application of the invention in the manufacture of framed laundry soap.

Example I V.-A framed soap comprised of'the sodium salts of fatty acids derived from a mixture of 1 part by weight of coconut oil and 1 part of a mixture of beef tallow and :hog fat and cottonseed .oil was used in this example. The soap contained about 39% by weight of water, 17% of sodium =.silic.ate solids, and about 42% of the anhydrous salts .of said fatty acids. Bars of this soap which were at a temperature of were cut with wires that served as cathodes with the bars lying on anode plates. Using a volt D. C. supply, 6.4-4 ampere of current per lineal inch of cathode were passed through the soap producing a glazed surface having a much higher luster than the surface produced by a wire which was not electrically lubricated.

Electrical lubrication can also be used to facilitate the stripping or removal of molds from detergent compositions, in which the latter :have been allowed to cool or harden, by using .the mold as the lubricated electrode and contacting an exposedsurface of the detergent cornposition with an electrode .of opposite polarity.

it has been shown that temperature has an important effect on electrical lubrication. Moisture content is also important in that as the bar approaches the anhydrous condition its electrical conductivity falls off rapidly and it thus necessitates the use of higher voltages to obtain the desired lubrication of the electrode surfaces. The optimum voltage to employ will vary, it being a function of the specific conductivity of the detergent composition employed, the distance that the current must travel through said materialand the area .of the electrodes.

Theelectrical lubrication .efiiects described above the examples relating to soap are also obtained with anionic synthetic organic detergents and their mixtures with soaps. Obviously adjustments are made in operating conditions to correspond to the conductivity and other physical aspects of the synthetic detergent, as have already been noted for soaps.

The accompanying drawings illustrate a preferred form of apparatus, which is typical of that used in the above examples of extrusion, although various modifications of the construction may be used. Thus in the case of the extrusion apparatus wherein potentials of well over 300 volts are employed across the orifice and the extrusion machine body a vary hazardous condition exists. It is therefore desirable to completely insulate the electrical system and provide shields and guards to prevent human contact with the machine and the extruded soap bar for a distance of several feet from the orifice. The hazard may also be reduced by mounting the non-lubricated electrode inside the extrusion chamber completely insulated from the body .of the machine. The hazard may be further reduced by mounting the anode and cathode close together so as to reduce stray currents and permit the use of lower voltages. The endless belt that conveys the extruded bar away from the orifice, particularly if it is grounded, may also be used as the non-lubricated electrode in conjunction with not only the electrically lubricated orifice but also with the electrically lubricated wire or knives used for cutting the bar into uniform lengths and shapes. it may become desirable when electrically lubricating cutting devices such as knives or wires to employ condensers in the electrical system especially at high voltages to prevent charring of the detergent through electric arcs developed as the cutting devices make and break contact with the detergent, or to use the moving belt or table as an electrode to cut down the current density thereby eliminating overheating and .charring of soap at. said electrode. 1 thus contemplate, in the practice of my invention, variations such as changes in size, position, polarity and potential of electrodes which may be employed as shaping devices to suit the needs of the detergent composition, electrical and mechanical controlling devices, safety devices, electrical equipment necessary for the safe, economical and elficient utilization of-the invention, and such changes and modifications as would normally occur to those skilled in the arts to which the invention relates.

This is a continuation-impart of patent application 50,498 filed September .21, 1-948, now abandoned.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In the process of ext sion of plastic bar of detergent compositions consisting essentially of soap high in mechanically produced beta phase and containing also soap in the unsolidified neat soap phase, said detergent compositions being in a condition of pasty cohesiveness, the steps of establishing an extrusion temperature within the beta-forming region and above the temperature range in which smooth surfaced soap is obtained in absence of electrical lubrication, and passing a direct electric current at a potential not in excess of 400 volts across the interface between the extrusion orifice and the extruding soap at a current density of 0.2 to 25.0 amperes persquare inch of electrically conducting interface at a rate of 0.1 to 10.0 coulombs per square foot of extruded bar 10 surface, to produce an extruded soap having a smooth surface.

2. The process of claim 1 wherein a current density of 0.5 to 5.0 amperes per square inch of electrically conducting interface is used at a rate of 0.7 to 7.0 coulombs per square foot of extruded bar surface.

3. The process of claim 2 in which the orifice serves as the cathode.

References Cited in the file of this patent UNITED STATES PATENTS 1,074,638 Moltz Oct. 7, 1913 2,032,624 Lyons Mar. 3, 1936 FOREIGN PATENTS 619,941 Germany Oct. 10, 1935 

1. IN THE PROCESS OF EXTRUSION OF PLASTIC BAR OF DETERGENT COMPOSITIONS CONSISTING ESSENTIALLY OF SOAP HIGH IN MECHANICALLY PRODUCED BETA PHASE AND CONTAINING ALSO SOAP IN THE UNSOLIDIFIED NEAT SOAP PHASE, AND DETERGENT COMPOSITIONS BEING IN A CONDITION OF PASTY COHESIVENESS, THE STEPS OF ESTABLISHING AN EXTRUSION TEMPERATURE WITHIN THE BETA-FORMING REGION AND ABOVE THE TEMPERATURE RANGE IN WHICH SMOOTH SURFACED SOAP IS OBTAINED IN ABSENCE OF ELECTRICAL LUBRICATION, AND PASSING A DIRECT ELECTRIC CURRENT AT A POTENTIAL NOT IN EXCESS OF 400 VOLTS ACROSS THE INTERFACE BETWEEN THE EXTRUSION ORIFICE AND THE EXTRUDING SOAP AT A CURRENT DENSITY OF 0.2 TO 25.0 AMPERES PER SQUARE INCH OF ELECTRICALLY CONDUCTING INTERFACE AT A RATE OF 0.1 TO 10.0 COULOMBS PER SQUARE FOOT OF EXTRUDED BAR SURFACE, TO PRODUCE AN EXTRUDED SOAP HAVING A SMOOTH SURFACE. 